Semiconductor devices are produced and used throughout the world in electronic and various other types of devices. Semiconductor devices are formed on semiconductor chips, and are often referred to as chips, which include millions of features and components that combine to form an integrated circuit or other semiconductor device. There is a constant push to increase integration levels of semiconductor devices by including more components on a chip of a given size, so that the increased functionality can be achieved on each semiconductor device chip. As such, semiconductor device features continue to shrink and there is an ongoing drive to shrink features and components further. One aspect of feature sizes that continue to shrink is the production of high aspect ratio features on or in a substrate.
For example, the lateral dimensions of holes, trenches, gaps, or other features that extend downwardly into a substrate or into a film or films formed over a substrate, continue to shrink. Advanced processing techniques allow for these holes, trenches, or gaps with shrinking lateral dimensions to be formed deeper and deeper into substrates or film or films formed above the substrates. As such, the aspect ratio continues to become greater.
Practically every substrate upon which semiconductor devices are being formed undergoes multiple wet processing operations. The wet processing operations include cleaning operations and etching operations. As the aspect ratio of holes, trenches, or gaps formed on or over the substrate become greater, it becomes increasingly more difficult for the cleaning or etching solvents to extend downward to completely fill the holes, trenches, or gaps and the efficiency of the cleaning process becomes lower. If the etching or cleaning solvent does not extend to the bottom of the holes, trenches, or gaps, undesirable residue or debris can remain after cleaning operations and undesirable material intended to be etched, can remain after etching operations. This is due, at least in part, to surface tension of the solvent liquid that is introduced onto the surface as an etching or cleaning fluid, and can also be due to reaction products or by-products.
There is also a solid-air surface tension on the surface of the substrate that can result in voids, i.e. air bubbles, when a substrate is undergoing wet processing. This results in small areas on the substrate that are not reached by the solvent liquid.
Also, it is difficult for the wet solvent that is used in the cleaning or etching process to flow into and out of voids or openings that may exist in microscopic residue, debris, or contaminants on the substrate.
To enhance the particle removal efficiency, some cleaning methods use physical force, such as megasonic power, ultrasonic power, or fluid jet to assist the solvent in removing undesirable residue. However, the physical force or pressure from the sprayed solvent may cause lateral damage, such as pattern collapse (e.g., photoresist layer or permanent layer), especially in advance node devices.